Volvo Maintenance Hints for 7xx/9xx - Bill Garland's Nuclear ...

Mine gave out at 48,000 miles. When it fails, you will have 3rd gear only and the check
engine and tranny dash lights will go on. The switch R&R at a Volvo dealer runs between
$300 and $400. I decided to buy the switch from Nils Sefelt Volvo in Houston on the
Internet for $110.00 plus $8.00 shipping UPS instead, and do the labor myself. [Tip from
JohnG] DO NOT purchase an aftermarket (Scan Tech) switch. Spend the extra $10-$10
and get an OE one.... trust me.
PNP Replacement. [Procedure by Walt Poluszny/John Gislason]
Removing PNP Switch:
1. Do not undertake this until you have the replacement switch in hand: cleaning the
old one will not work.
2. Raise the front of the car; jack stands are preferable.
3. Chock wheels and put transmission in Neutral.
4. Apply penetrating oil to the six (4 front, 2 rear)14 mm exhaust pipe nuts.
5. If needed, remove three 10 mm bolts that hold on the O2 Sensor wiring to the trans.
cross member.
6. Remove one 10 mm nut and three plastic wire retainers for O2 Sensors on frame
above Cat. Conv.
7. Loosen all six 14mm exhaust nuts, drop the rear of the pipe. Remove 3 of the 4
front 14 mm nuts so that 1 nut is still holding the pipes up. Pipe should swing from
side to side to make clearance to the PNP switch. [Editor] Plan on rusted nuts
which may have to be cut off.
8. If needed, remove two 10 mm nuts & fender washers holding heat shield above
Cat. Conv. on
9. If needed, disconnect 17 mm trans. cooler return line on transmission. This line is
usually installed very tight and dry. I suggest buying a very good quality flare nut
wrench and soaking it 4-6 times overnight with PBlaster or a penetrating oil. Use
two wrenches, one on the fitting itself and the other on the nut. You will have to give
it a whack to pop it loose then apply teflon tape to the threads when you re-install.
[James Steven] This step may not be needed. I was able to remove and replace the
switch with the exhaust and cooling line in place; putting the gearshift in neutral
permitted rotation of the switch housing until it cleared the cooling line.
10. Allow trans fluid to drain from fitting before continuing (approx. 1.5 quarts). Drains
slowly, will take about 1/2 hour.
11. Remove 12mm bolt from top of PNP switch. Caution : it is easy to round this nut. It
has a small head and is soft. Use a six point socket and take it slow.
12. Pry 4 metal retaining fingers away from 22 mm nut on PNP Switch shaft.
13. Remove 22 mm nut on PNP switch.
14. Evenly pull PNP switch off trans shaft.
15. Cut cable tie above PNP switch on the wiring harness.
16. Clip the remaining three cable ties and loosen the metal retainer on the drivers side
of the transmission holding the PNP switch wiring harness